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In a retrospective multicentre study, we aimed to correlate clinical factors and findings on plain radiographs and MRI with the intraoperative presence of Vickers’ ligament in Madelung’s deformity. We screened the records, in which the absence or presence of Vickers’ ligament was affirmatively indicated, of 75 consecutive operated extremities in 58 patients. In 83% a Vickers’ ligament was observed intraoperatively. The whole bone Madelung type (as opposed to the distal type) and a distal radial notch were independent, significant predictors for the presence of the ligament. The correct Vickers detection rate using MRI was 85% of the 27 cases for which MRI was available. Thus, the MRI was a good but not perfectly reliable modality. We conclude that Vickers’ ligament is present in the majority but not all cases with Madelung deformity. We advise that patients with a more severe type of Madelung’s deformity and a distal radial notch should be monitored closely. Level of evidence: IV

Background Fractures of the anteromedial facet of the coronoid in posteromedial rotatory instability of the elbow are classified into 3 subtypes based on their location. The purpose of this study was to analyze the fracture morphology of anteromedial facet fractures in their 3 subtypes (anteromedial rim, anteromedial rim + tip, and anteromedial rim + sublime tubercle [±tip]). Methods Three-dimensional computed tomography remodeling was used to evaluate anteromedial facet fractures in a consecutive series of 40 patients, all of whom were affected by posteromedial rotatory instability of the elbow. Characteristics of the fractures, including the number of fragments, size of fragments, plane of the fracture line, and involvement of the sublime tubercle and radial notch, were measured for each subtype of the anteromedial facet fractures. Results Each subtype had a typical fracture pattern and distinct size. The fracture subtype 1 showed a single-fragment fracture, subtype 2 showed either a single- or dual-fragment fracture, and subtype 3 showed either a dual- or triple-fragment fracture. The angle between the fracture line and the coronal plane was greatest in subtype 3 fractures. The surface area of the fragment was largest in subtype 3 fractures. The percentages of articular involvement of the sublime tubercle were 0% in subtype 1, 47% in subtype 2, and 79% in subtype 3. The percentages of articular involvement of the radial notch were 0% in subtype 1, 7% in subtype 2, and 8% in subtype 3. Conclusion Analysis with quantitative 3-dimensional computed tomography showed the characteristic morphology of each subtype of anteromedial facet fracture. Subtype 1 comprised 1 fragment with the smallest fragment size. Subtype 2 was a single- or dual-fragment fracture, the size of which should be considered in the treatment plan. Subtype 3 was a large fragment comprising the sublime tubercle. Our findings are significant because they highlight unique fracture morphology that may help surgeons to distinguish one fracture subtype from another in clinical practice.

The proximal radioulnar joint (PRUJ) and the radiocapitellar joint may be destabilized after trauma. Different techniques for stabilization of PRUJ have been proposed, but none of them can stabilize the radiocapitellar joint at the same time. We propose a ligamentoplasty to stabilize the radial head at these two joints by reconstructing the radial head annular ligament and the lateral collateral ulnar ligament (LCUL) with a single graft (palmaris longus or gracilis tendon of the knee). Fifteen cadaveric upper limbs were used to compare the stabilization obtained by performing our ligamentoplasty with the palmaris longus or the gracilis tendon. For each technique, the stabilization obtained was evaluated by measuring the displacement of the radial head in the anterior, lateral and posterior directions when a force of 1 N was applied in maximum supination, neutral rotation and maximum pronation. We also evaluated whether this technique could damage the ulnar nerve or the posterior interosseous nerve by dissecting them and whether it could limit the range of rotation of the forearm. Our ligamentoplasty enables to restore PRUJ stability equivalent to the intact ligament condition. The palmaris longus was inconstant (13/15) and too short to allow concomitant reconstruction of the LCUL (except in one case). No nerve damage was found during the dissection, and the range of rotation of the forearm was not limited by the ligamentoplasty. We also report a clinical case with an excellent result and without complications. This ligamentoplasty we have described makes it possible to stabilize the radial head with respect to the radial notch of the ulna and with respect to the capitellum of the humerus. The gracilis tendon is more suitable than the palmaris longus because of its constant presence and length. A clinical series is now necessary to better evaluate this technique.

Introduction The elbow joint is a compound joint made of articulations in between the humerus, ulna and the radius. The coupling areas (joints) are of prime importance from the kinetic-biomechanical perspective and of potential inter-ethnic significance. These articulations can be affected by several pathologies that may require medical and surgical interference. This experimental analysis aims to infer data in relation to the morphometry of the proximal segment of the ulna and its articular surfaces represented by the greater sigmoid notch (trochlear notch) and lesser sigmoid notch (radial notch). Methods A sample of fifty ulnae (n = 50, 27 right and 23 left) was studied in connection with; the surface area of the sigmoid notches (SA), weight of ulna, and the volume of proximal portion of ulna (including the olecranon process and reaching inferiorly to the lowest margin of the radial notch), the length of ulna (L). Longitudinal dimensional parameters were also studied including; the straight distance between the highest point (tip) of the olecranon and that of the coronoid process (OCD), and the mid-olecranon thickness in mediolateral (T1) and anteroposterior orientation (T2). Results It has been inferred that there were no significant differences in between right versus left ulnae and in relation to the majority of morphometric parameters with an exception for OCD (22.47 vs 20.75, p-value = 0.002). There was a positive correlation in between all the parameters, although the strongest associations were observed in between OCD, the area of the trochlear notch, and the weight of ulna. Discussion A precise conclusion was reached in relation to morphometry, volumetry and the pertinent biomechanics of the proximal segment of the ulna. Key findings are of value to biomedical engineers, medical professionals including orthopaedic surgeons and rheumatologists, evolutionary biologist, and physical anthropologist. Data from this study can be used to (reverse) engineer the perfect implant for the elbow joint.

The objective of this study was to provide the detailed normal gross osteology and radiographic anatomy of the thoracic limb in goats as a reference for clinical use and in biomedical research. Radiography of the thoracic limb was performed in five small East African goats. Radiographic findings were correlated with bone specimens from four adult small East African goats. The scapula was narrow. The major tubercle was large and extended proximally above the head of the humerus. The lateral supracondylar crest was less prominent. The lateral and medial epicondyles of the humerus were almost of the same size. The lateral surface of the lateral condyle of the humerus presented a prominent depression for the origin of extensors of the carpus and digits. The cranially located radial notch was deep seated and the radial tuberosity was represented by a rough area located nearer to the head of the radius. The fifth metacarpal bone was seen in all animals. The morphology of the thoracic limb of small East African goats indicated the presence of powerful extensor muscles and is restricted to forward and backward movements as an adaptation to terrestrial lifestyle.

Traumatic lesions of the distal radio-ulnar joint (DRUJ) occur frequently in conjunction with fractures of the distal radius. They are a common cause of pain and limited range of motion after distal radial fractures. Due to the complex anatomy they are however often ignored or underappreciated. Distal radial fractures and luxations of the DRUJ often disturb the normal curvature of the radial notch and cause damage to the cartilage of this joint. The growth of the radius may be disrupted, resulting in a positive ulnar variance, and possibly give rise to complications such as ulnar abutment and motion restriction. Ulnar styloid fractures - sometimes barely visible on plain film - may give rise to symptomatic bony pseudarthrosis, dislocation and laceration of the tendon of the m. extensor carpi ulnaris and a rare posttraumatic deformity of the ulnar epiphysis. Also the possibility of lesions at the adjacent triangular fibrocartilage complex and the joint capsule should be kept in mind. This paper presents a pictorial review of the complex functional anatomy and pathologic conditions of this joint and emphasises why the DRUJ should be evaluated independently and thoroughly. The merit of each imaging modality is mentioned. A correction article relating to Fig. 2 and Fig. 27 can be found here: http://dx.doi.org/10.5334/jbr-btr.966

© 2019 American Society for Surgery of the Hand Purpose: The anatomy of the radial head and capitellum has been extensively studied; however, the anatomy of the radial notch of the ulna (RNU) has received little attention. This imaging-based anatomic study characterizes the morphology of the RNU. Methods: Ninety-eight cadaveric arms (57 male, 72 ± 14 y) were imaged with computed tomography, and 3-dimensional reconstructions of the proximal ulna were constructed. The anteroposterior and proximal-distal dimensions of the RNU as well as the radius of curvature at standardized levels were measured in 2-mm increments. The orientation of the RNU was also determined. Results: The proximal-distal and anteroposterior dimensions of the RNU were 12 ± 2 mm (range, 7–16 mm) and 18 ± 3 mm (range, 12–24 mm), respectively. The average radius of curvature of the RNU was 15 ± 0 mm (range, 15–16 mm). The radius of curvature did not change significantly when comparing the proximal and distal aspect of the RNU. The RNU was rotated 33° ± 2° (range, 31° to 38°) externally relative to the transverse plane of the ulna. The average depth of the RNU at its deepest point was 2.2 ± 0.4 mm (range, 1.5–2.7 mm). The depth decreased from proximal to distal, being most shallow distally. The depth changed by an increase of the radius of curvature, as well as by rotation in the frontal plane. Conclusions: The RNU anatomy was variable, generally extending laterally from proximal to distal. This suggests that a radial head implant should taper from proximal to distal to optimize contact at the RNU. Clinical relevance: The present study investigates the detailed anatomy of the radial notch of the ulna using computed tomography scans. The data might help improve the design of prosthetic components.

Background Chronic posterior subluxation or dislocation of the radial head is uncommon and difficult to treat. To restore radiocapitellar alignment, procedures such as deepening of the notch using a high-speed burr have been described, but they can result in cartilage damage. We hypothesized that a radial notch labralization using soft tissue could improve radiocapitellar tracking without violating the joint surface. Methods A radial notch labralization was performed in 3 patients with chronic posterior subluxation of the radial head and developmental dysplasia of the radial notch in the setting of complex recurrent instability of the elbow. A soft tissue graft (typically a portion of an allograft hamstring tendon) was used to create a meniscus-like bumper posteriorly, thereby deepening the radial notch and reducing its radius of curvature. A corrective anterior opening wedge ulnar osteotomy was also performed to realign the radial head with the capitellum. Results At a mean follow-up of 32 months, all 3 patients were pain free and had maintained a stable joint, with a functional range of motion. Each patient gave a rating of either "Greatly Improved" or "Almost Normal" on the Summary Outcome Determination scale. Radiographs performed during the last follow-up showed improved radiocapitellar alignment. Conclusion Chronic posterior subluxation or dislocation of the radial head can occur subsequent to developmental joint changes. The radial notch labralization using a soft tissue graft associated with a corrective ulnar osteotomy was successful in restoring radial head stability and avoiding cartilage damage.

A study of the supinator crest of ulna was carried out in 387 dry ulna bones and by dissection of 23 upper extremities of cadavers and a foramen in the supinator crest of ulna was found close to the radial notch in 5.75 of bones. In the cadaveric dissection study it was found that a branch of ‘Interosseous Recurrent Artery’ passed through this foramen of ‘Supinator Crest’. This study is very significant because the existing textbooks of anatomy and available literature do not describe any such foramen or groove of supinator crest through which a branch of interosseous recurrent artery passes.

The elbow is a complex articulation comprising the radius, ulna, and humerus. The radius and ulna function in concert with the distal humerus to allow flexion and extension at the elbow, while the radius and ulna separately allow supination and pronation. As a main transfer point of forces between the upper and lower arm, the elbow serves as the insertion site for a number of muscle tendons, all of which exert substantial forces at their attachment sites. During infancy, the elbow’s articular surfaces cannot be seen radiographically, as they are not as yet ossified. As the child grows, an ordered progression of ossification occurs at the secondary centers as the elbow joint gradually reveals its structure. The capitellum is the first secondary ossification center to ossify, occurring at about 1 year of age. Next, the radial head ossifies at about 3 years of age, followed by the internal (medial) epicondyle at 5 years, the trochlea at 7 years, the olecranon at 9 years, and finally the lateral epicondyle at 11 years. The progression lends itself to an easy mnemonic (“CRITOE”) with the ossification progressing approximately every 2 years in most cases. Some variability in the age of ossification of the various centers is common. When faced with an unusual pattern of ossification, views of the contralateral elbow can be very helpful. In truly difficult cases, advanced imaging may be needed, primarily ultrasound and magnetic resonance imaging (MRI). The configuration of the various ligaments and tendons about the elbow is the same as in the adult. The ulnar collateral ligament (UCL) medially has anterior, posterior, and transverse bands of which the anterior and posterior bands are most important. The anterior band spans the gap from the medial epicondyle to the sublime tubercle (Figure 1A). The posterior band is the weaker of the two and extends from the medial olecranon to the posterior aspect of the medial epicondyle (Figure 1B). Laterally, the radial collateral ligament and the lateral band of the UCL are the main restraints to varus stress, with the latter being the primary support. Both arise from the lateral epicondyle. The lateral band of the UCL wraps along the underside of the radius, cradling it, and inserts on the lateral ulna at the supinator crest (Figure 1A). The annular ligament, as its name suggests, encircles the radial head with insertions on the posterior and anterior aspects of the ulna at the radial notch. Figure 1. Twelve-year-old boy. A, coronal T2 fat-saturated magnetic resonance. The anterior band of the ulnar collateral ligament stretches from the underside of the medial epicondyle to the sublime tubercle (arrowheads). The lateral band of the ulnar collateral ... Given its varied appearance and multiple-tendon and ligamentous appearance, a multimodality approach to elbow imaging is best. Especially in pediatrics, radiographs remain the mainstay of initial investigation, since they are fast and inexpensive and usually include sufficient information to guide therapy in the majority of cases. However, other modalities make substantial contributions to the diagnosis and care of both acute and chronic injuries about the elbow through childhood and adolescence. Computed tomography scanning with its multiplanar capability is adept at producing highly intelligible images with excellent resolution. Ultrasound has the advantage of not requiring ionizing radiation but tends to be a more focused examination without the ability to obtain a global picture of the joint. MRI is the primary advanced imaging modality, as it does not require ionizing radiation and can visualize bone as well as articular, physeal, and epiphyseal cartilage. The key to understanding elbow injuries in the child is an appreciation of the weak links in the structure of the elbow. The physis is a mainly columnar aggregation of chondrocytes with scant intervening matrix. As such, it is always weaker than bone and is much more likely to fail in the face of acute or chronic repetitive trauma. Much of pediatric elbow imaging focuses on the evaluation of the multiple growth centers and their physes about the elbow. The distal humerus also includes a thin supracondylar portion, which, when exposed to the force of the olecranon, is much more likely to fracture compared with the more substantial physes at the larger portion of the distal humerus. Supracondylar fractures are common as an acute sports injury, as are lateral and medial condylar fractures. In many cases, after acute trauma no fracture will be noted on conventional radiographs. However, prominent anterior and posterior fat pads indicate a joint effusion and alert the physician of the likelihood of an occult fracture (Figure 2). The elbow can then be immobilized. Follow-up films done 10 to 14 days later will commonly show periosteal reaction, indicating that a fracture had indeed occurred. Figure 2. Six-year-old boy. Lateral view of the elbow demonstrates a prominent anterior far pad (arrowhead) and posterior fat pad (arrow). A fracture of the proximal ulna is present (curved arrow) As children grow and mature, they participate in sports in a more goal-directed manner. In addition to a greater time actually playing sports, a greater amount of time is spent practicing. The greater load of repetitive motion leads to an increased incidence of overuse injuries about the elbow. As the ossification centers about the elbow develop and mature, the pattern of injury changes as well. In the United States, sports-related injuries of the pediatric elbow mainly result from baseball and gymnastics. During throwing, the arm is extended posteriorly, or “cocked,” and then accelerated forward to propel a projectile toward the target. During the late phase of cocking and early acceleration, a large hyperextension and valgus force is placed on the elbow. The result is a lateral compressive force centered on the developing capitellum laterally where the pattern of injury depends on the state of maturation of the capitellum. A great tensile or distractive force is concurrently borne by the medial supporting structures. Here again, the injury changes with age as the skeleton goes through its predictive pattern of maturation. Although the actual mechanism of injury is identical to the syndrome of valgus extension overload common in adult professional baseball pitchers, the appearance changes since the skeletal structures are different. A typical pattern of injury emerges. Laterally, Panner disease is seen first. This injury is thought to be an osteochondrosis of the capitellum seen in athletic individuals less than about 12 years old. In athletes older than 11 years, osteochondritis dissecans (OCD) occurs and is akin to OCD elsewhere in the body, as at the femoral condyles and talus. As can be seen, there is some overlap in the age ranges in the 2 syndromes reflecting to a certain extent their common etiologies. In skeletally mature individuals, true osteochondral fractures of the capitellum may occur. Medially, injuries also progress in a fairly predictable manner. In younger adolescents, the medial epicondyle with its relatively weak physis is mainly affected. As physeal fusion nears, the focus of the injury shifts to the UCL as the main restraint to valgus forces is overcome. At the medial margin, many mixed forms are present such that partial tears of the UCL may coexist with chronic physeal injury at the medial epicondyle. Interestingly, chronic physeal injury at the medial epicondyle weakens it and may result in a complete avulsion of the entire medial epicondyle with displacement. Posteriorly, the main injury is to the olecranon at the level of the physis. Here the triceps caused a chronic avulsive injury to the olecranon physis and persistence of the olecranon physis. In addition to injuries related to throwing a baseball, elbow injuries related to gymnastics are also very common. The pursuit of excellence in gymnastics requires long hours of training in which the same routines and exercises are practiced repetitively such that the arms are subjected to a remarkable degree of repetitive stress. Injuries at the wrist are well documented and include a range on injuries whose manifestation depends on the skeletal maturation of the athlete. Elbow injuries are also common and include some of the same injuries that baseball players sustain especially laterally. Apart from acute fractures, football injuries are underrepresented in the scope of injuries about the elbow. The reason for this discrepancy is related to the actual shape of the football as opposed to the baseball. A baseball is small and round and fits easily into the palm of the hand. It is meant to be thrown, and indeed, all the players on the field, not just the pitcher, throw the baseball an enormous number of times. In contradistinction, the football is not a ball that is easy to throw. It is far heavier than a baseball and does not lie well in the hand. It is much more difficult to throw hard so that the throwing motion is far less extreme in terms of the acceleration of the arm and the extent of cocking that occurs during throwing. In addition, most of the players on a football team do not ordinarily throw the ball. In fact, most of the players on a team do not touch the ball at all during the course of the game.

The determination of sex is one of the fundamental assessments in the production of a biological profile for human skeletal remains, and a large number of studies have focused on evaluating sexual dimorphism metrically. A recent study of a contemporary American population presented high classification accuracies from discriminant function analysis of the proximal ulna (Grant and Jant,2003). The present research tests this method using a large sample (223 skeletons: 114 males and 109 females) from two skeletal assemblages of European origin, the documented Spitalfields Coffin-Plate Collection (N = 171) and the archaeological Raunds Furnells Collection (N = 52). The three measurements from the original study (Grant and Jantz,2003), defined as the notch length (NL), the width of the olecranon process (OW), and the height of the coronoid process (CH) were tested, with the addition of a new variable radial notch height (RNH). Significant differences (P < 0.001) were found between male and female ulna measurements. Discriminant analysis found the original discriminant equation classified individuals with accuracies of only 40% for males but 99% for females. New discriminant functions were developed using direct and stepwise analyses of the Spitalfields sample. A direct multivariate function based on four dimensions (NL, OW, CH, RNH) produced an overall classification accuracy of 85.4% (males 82.4%; females 88.4%). A second function based on the original three measurements (NL, OW, CH) yielded nearly identical classification accuracies (males 81%; females 88.5%). Crossvalidation of the Spitalfields data using the three-variable function yielded an overall classification rate of 84.2%. This study indicates that the ulna is sexually dimorphic but its development is population-specific. Am J Phys Anthropol, 2008. © 2008 Wiley-Liss, Inc.

To develop a schematic segmentation of the proximal ulna in order to detect, assess the frequency, and characterize the bony outgrowths arising from the trochlea and from the radial notch of the ulna, to enable differentiation of osteophytes from enthesophytes. Eighty well-preserved ulna specimens from the collection of the San Diego Museum of Man were analyzed by two musculoskeletal radiologists. The trochlea and the radial notch of the ulna simulate the shape of a clock quadrant. The proximal ulna was divided into 24 anatomic areas. The relationships of the joint capsule and insertions of tendons and ligaments onto these area were assessed by the two readers, and the resulting appearances of bony outgrowths were compared at visual inspection and on Radiographs. The interobserver visual comparison was good in 17 areas out of 24, but poor correlation was found in 7 areas. In one case, difficulties in differentiating osteophytes originating from the brachialis muscle/ tendon (area 9) from an enthesophyte originating from the capsule insertion on the coronoid process (areas 2 or 3) occurredand between two different enthesophytes in a further case. Five cases had difficulties in defining differences in the grading system of the outgrowths. The percentage of outgrowths observed in each of the areas was globally high, especially in areas 9 and 10. On radiographs it was possible to observe irregularities in ten areas; in eight at a threshold of height of 2 mm (areas 1-4, 9, 10, 11, 14) and in two at a threshold of height of 3 mm (areas 5, 6). The two readers had the same difficulties in differentiating enthesophytes from osteophytes at radiographic and visual examination. Our segmentation scheme is reproducible and objective, and permitted the differentiation of the bony outgrowths arising from the proximal ulna into osteophytes and enthesophytes, which may be particularly useful for the in vivo assessment of abnormalities seen in elbow overuse syndromes.

The simplest phenomenological models of materials having different resistances to tension and compression are constructed using a rheological method supplemented by a new element — a rigid contact. The problems of the solvability of static boundary-value problems for small deformations of the medium are considered within the framework of the regularized model. A generalization of the static and kinematic theorems of the theory of limiting equilibrium is given. The upper bound of the limiting load and the angle of emergence of the linear zone of deformation localization in the problem of the rupture of a cylindrical specimen with a radial notch when there is pressure on the sides of the notch is obtained as an example of the application of these theorems

Purpose The purpose of this study was to define the shape of the radial head by identifying the relationship between precisely defined axes of the radial head. Methods An anatomic study was done to define the shape of the radial head and specifically the relationship between the long and the short axis. Twenty-seven cadaveric upper extremities were used. The x and y axes of the radial head were defined in relationship to the radial notch of the ulna, with the forearm in neutral position. Outer diameters of the x and y axis were measured. These were compared with the actual maximum and minimum diameters of the radial head. X and y diameters of the articulating surface of the radial head also were measured. Paired 1-tailed Student's t -tests were used to compare the x and y diameters of the radial head. Regression analysis of x and y diameters of the radial head was done to identify a correlation between these parameters. Results Paired 1-tailed Student's t -tests showed a significant difference between X and Y diameters of the radial head. Regression analysis of x and y diameters of the radial head showed a strong correlation between these 2 axes. Conclusions The radial head is not round. A strong correlation exists between the x and y diameters of the radial head. The orientation of the long axis is perpendicular to the radial notch with the forearm in neutral rotation. This finding will make it possible to approach the anatomy of the radial head more closely when designing radial head prostheses. The definition of the axes can be used as a guide when implanting the radial head prosthesis.

We examined radiographs of the elbows of the pitching arms of 79 professional baseball pitchers (mean age, 25.1 years; mean duration of professional career, 4.7 years) and noted the frequency and size of spurs, bone fragments, and intra-articular loose bodies according to site. The influence of duration of professional baseball career on these osteoarthritic changes was also investigated. The olecranon tip was the most frequent site of spurs (62/79; 78.5%), and fragmentation of the spur was detected in 17 joints. The frequency of spurs was also high at the medial margin of the olecranon, the tip of the coronoid process, the medial margin of the sigmoid notch, the medial margin of the trochlea and the olecranon fossa. In 38 subjects, spurs were observed at the distal portion of the radial notch of the ulna. However, few pitchers had osteoarthritic changes in the humeral capitellum or radial head. Intra-articular loose bodies were detected in 4 of 79 joints (5.1%), and bone fragments were present below the medial humeral epicondyle in 25 of 79 joints (31.6%). Osteoarthritic changes in the elbow joint appeared to be attributable mainly to traction stress and impingement associated with extension and valgus strain. Significant osteoarthritic changes were often found in professional pitchers whose careers exceeded 5 years.

Determination of sex constitutes the most important element during the identification process of human skeletal remains. Several sex-specific features of human skeleton have been exploited for sex determination with varying reliability. This study aims to obtain sexual dimorphic standards for ulnae of the north Indian population. Eight measurements were obtained on a sample of 106 ulnae (males--80, females--26) in the age range of 25-65 years. The sexual dimorphism index and demarking points were calculated for all the variables. The data were then subjected to stepwise and direct discriminant function analysis. The best discriminator of sex was the maximum length (84.9%) followed by radial notch width (84%). In stepwise analysis, these two variables were selected and provided an accuracy of 88.7% (M-87.5%, F-92.3%). The proximal end provided a classification rate of 81.1% (M-80%, F-84.6%) with selection of the notch length and olecranon width.

Analysis of a recently discovered partial skeleton of Prolimnocyon atavus, an early Eocene creodont (Hyaenodontidae, Limnocyoninae), from the Willwood Formation of the Bighorn Basin, Wyoming, demonstrates that its postcranial skeletal anatomy was most similar to that of extant scansorial procyonid, viverrid, and mustelid Carnivora. Its anatomical traits (including reduced greater tuberosity, prominent and sharp deltopectoral crest, well-developed entepicondyle and brachial flange, ovoid radial head and gently concave, laterally oriented radial notch, moderately deep, laterally compressed ungual phalanges, medially projecting lesser trochanter, flattened talar trochlea with high lateral rim, helical proximal cuboid facet) are commonly associated with joint mobility and abducted limb posture which, in extant mammals, are characteristic of scansorial and ambulatory locomotion. These features resemble those of some early Eocene proviverrine hyaenodontids and, to a lesser extent, miacid Carnivora, but...

A 20-week-old male golden retriever, which was not lame and showed no clinical signs of a fragmented medial coronoid process (FCP), was euthanased for another study and perfused intravenously with formaldehyde. Gross dissection revealed no abnormalities within the right elbow joint. The medial coronoid process was excised, embedded in methylmethacrylate, scanned in a microcomputed tomography (microCT) scanner and sectioned for histology. The microCT scans revealed a dense trabecular bone structure, much denser than in other dogs of similar age, which was considered to be responsible for the sclerosis visible at the base of the coronoid process in radiographs. Three-dimensional reconstructions indicated that there was a small step within the subchondral bone, extending from the apex towards the radial notch. Histology revealed a necrotic lesion between locally thickened articular cartilage and the subchondral bone, characteristic of osteochondrosis.

The medial coronoid process (MCP) of the ulna takes part in the weight-bearing function of the elbow in quadrupedal animals. In this study, the timing of development of a solid subchondral bone layer (SBL) of the MCP in the dog is investigated, as this might be important in the pathogenesis of the fractured medial coronoid process, a common disease in young dogs of larger breeds. The SBL is considered to make an important contribution to the strength of the MCP. In this study, the SBL is visualized at the humeral articular side (H-side) and in the radial notch (RN) via three-dimensional reconstructions of micro-CT scans (34 μm voxel size) in nine young golden retrievers. After micro-CT scanning, the area was investigated histologically. Gradually, the appearance of the SBL on the H-side changes from a trabecular aspect to an even surface with gaps and finally to a completely even surface. The surface in the RN is still rough at 24 weeks after birth, although some consolidation has occurred. Initially, the enchondral ossification activity, as observed in the histological sections, is high, but later, when the intertrabecular spaces are filled in with calcified cartilage and bone, activity is less evident. Some vessels penetrated the SBL, but it is unclear if they account for all the gaps in the surface seen in micro-CT. In addition, the formation of a cortical structure of the proximal ulnar shaft could be visualized. The bony cortex is already even at the mediocaudal side of the proximal ulna 4 weeks after birth, but remains trabecular at the dorsal side until 6 weeks later. We hypothesize that the observed differences in the formation of an even SBL or cortex can be explained by mechanical factors. A smooth cortical layer has an even thickness and will be stronger than a cortex with varying thickness. In the MCP, compressive forces exerted by the humerus may be responsible for the early smoothening on the H-side. In the proximal ulna, the resistance to bending in the sagittal plane will depend mainly on the caudal surface of the ulna (and dorsal surface of the radius), surfaces furthest away from the neutral axis. At least the caudal ulna smoothened first, thus providing stiffness against bending at an early age. © 2005 Wiley-Liss, Inc.

This paper investigates the possibility of crack detection for holes containing elastic inserts. A BEM model was formulated for the scattering response of an incident shear wave transducer signal by a cylindrical hole with a radial notch, an elastic insert, and a stiffness interface between the hole and the insert. Through simulated and experimental studies, certain interface conditions were identified for which significant interface waves can be generated and subsequently used for inspection purposes.

Background: Lateral ulnar collateral ligament (LUCL) reconstruction requires proper understanding and identification of anatomic structures about the lateral elbow. The insertion site of the LUCL is based on the supinator tubercle. Purpose: To characterize the supinator tubercle relative to other surrounding anatomic landmarks. Study Design: Descriptive laboratory study. Methods: Computed tomography (CT) scans of 10 adult elbows were retrospectively reviewed. These CT scans were converted into patient-specific 3-dimensional computer models. Using a user-defined coordinate system, an ulnar Cartesian coordinate system was defined with anatomic landmarks as reference points to standardize the position of each model. The length of the supinator crest was measured. Following this, the crest was examined for a distinct raised bony tuberosity that would be consistent with the supinator tubercle. If no distinctly raised tubercle was noted, the most prominent appearing location of the crest distal to the radial notch was considered the tubercle. The distance from the proximal radial head junction to the supinator tubercle was recorded. Finally, the distance from the supinator crest at the radial head junction to the posterior cortex in the sagittal plane was measured. Results: The supinator tubercle was found to be prominent in 5 of 10 ulnar models. The supinator crest was 43.59 ± 13.28 mm long, and the supinator tubercle lateral extrusion was 5.60 ± 0.90 mm. The distance between the radial head junction and the supinator tubercle was found to be 15 ± 2.37 mm, and the distance from the supinator crest at the radial head junction to the posterior cortex was 10.25 ± 2.07 mm. Conclusion: The supinator tubercle is frequently not prominent or easily recognizable. Its relationship to other structures is of value. The proximal border of the radial head, residing 15 mm proximal to the most predictable location of the supinator tubercle, is a useful landmark when drilling tunnels during LUCL reconstructions. Clinical Relevance: Results of this study may aid proper anatomic LUCL reconstruction.

Understanding the anatomical relationships in the region of the supinator muscle is crucial in limiting surgical morbidity. The course, length, and muscular innervations of the posterior interosseous nerve, as well as a detailed dissection of the supinator muscle, were described and recorded in 31 specimens from 16 adult cadavers. In our study, the radial nerve bifurcated into the posterior interosseous nerve and superficial radial nerve 8.0 +/- 1.9 cm distal to the lateral intermuscular septum. The bifurcation of the radial nerve occurred 3.6 +/- 0.7 cm proximal to the leading edge of the supinator, with the posterior interosseous nerve exiting the supinator muscle 3.8 +/- 0.9 cm distal to the proximal margin. The arcade of Frohse was membranous in 68% of our specimens and tendinous in 32%. The supinator had one semicircular head or layer in 71% of specimens and 2 distinct heads or layers, as defined by diverging muscle fibers, in 29%. With 2 heads, or layers, the superficial layer extended to the lateral epicondyle while the deep layer extended to the ulna, below the radial notch.

Elbow dysplasia is osteoarthrosis/degenerative joint disease due to abnormal development of the elbow joint. The abnormal development is the result of specific inherited etiologies alone or in combination. This paper attempts to clarify the diagnosis of elbow dysplasia based on the presence of degenerative joint disease by correlating radiographic, necropsy, and histopathologic results using elbows from 8 German Shepherd dogs. All elbows had radiographic changes consistent with osteoarthrosis/degenerative joint disease which were identified best on the flexed medial-lateral projection. Radiographically, a specific diagnosis was made in seven elbows; ununited anconeal process (6) and osteochondrosis (1). At necropsy these lesions were confirmed plus 14 elbows were identified that had fragmented medial coronoid process (6), abnormally shaped medial coronoid processes or fissures in the articular cartilage of the medial coronoid process (8). Additionally, histopathologically there was proliferative synovitis at the radial notch of the ulna and degenerative changes on the proximal, nonarticular surface of the anconeal process at the site of insertion of the olecranon ligament and joint capsule. Therefore, for screening the elbow joint to identify elbow dysplasia, the recognition of osteoarthrosis/degenerative joint disease on an extreme flexed mediolateral radiograph appears to be sufficient.

The proximal radio-ulnar joint has two different types of articular surfaces. The contact area between the articulating surfaces is at its greatest when the joint is in a middle position. The highest density of osseous material is found on the ulnar side of the head of the radius. The subchondral bone beneath the radial notch of the ulna has a higher density at the edges than in the middle. In photoelastic experiments the intensity and configuration of isochromatics correspond to the material density of the osseous tissue of ulna and radius. The analysis of spongiosa near the joint shows bands of compressive cancellous trabeculae radiating axially into the subchondral cortex, crossed at right angles by bands of tensile cancellous trabeculae. These findings are in agreement with the course of the trajectories found in photoelastic experiments. The composition of the annular ligament is variable. The palmar and dorsal parts are made up of firm connective tissue; opposite the radial notch of the ulna, however, cartilage cells are embedded in the ligament. The histological composition of the annular ligament and the cancellous architecture in the radius and the ulna are in agreement with Pauwels' (1963) hypothesis that part of the compressive force in the elbow joint is transferred to the proximal radio-ulnar joint via the annular ligament. The distribution of the material in the subchondral bony tissue indicates that there is only partial contact between the radial head circumference and the radial notch of the ulna in all positions of the joint.

The K calibration for an internally pressurized, thick-wall cylinder with a straight, radial notch has been determined from a compliance test. The method suggested by Irwin is used with compliance defined as the change in internal volume of a cylinder divided by applied hydrostatic pressure rather than the usual load-elongation definition. The derivative of internal volume change with respect to notch depth, a . is obtained by numerical analysis of tangential strain measurements on the o.d. of the test cylinder. This derivative leads directly to the K calibration for the cylinder. Cubic spline functions are used to approximate both the strain as a function of position on the cylinder and the resulting volume change as a function of a . Also included in the determination of K is a proof, using the divergence theorem in the theory of elasticity, that the derivatives with respect to a of internal and external volume change are identical. This allows the use of external strain measurements to determine K based on internal volume change. The compliance K calibration nearly coincides with a semi-infinite plate solution simulating both the tangential stress due to pressure and the direct effect of pressure in the notch, K I = 1. 12 σ θ √ πa + 1.13 p √ πa . This unexpected agreement, particularly for values of a / w up to 0.6, is explained by the combination of bending constraint and drop off of tangential stress in the cylinder wall.

The elbow joint is formed by the distal end of the humerus and the proximal ends of the radius and ulna. The superior radio-ulnar joint, between the head of the radius and the radial notch of the ulna and annular ligament, has a joint cavity continuous with that of the elbow joint. The inferior radioulnar joint, between the head of the ulna and the ulnar notch of the radius, has no communication with the wrist joint as a rule. The union by the interosseous membrane of the shafts of the radius and ulna is, by strict definition, a fibrous joint between the radius and ulna and is sometimes called the middle radio-ulnar joint.

Anatomical and pathological descriptions of five congenital elbow luxations and subluxations in three dogs were based on palpation, radiographs, gross dissection and in one dog, surgical correction. The primary defect in all five joints was hypoplasia, or aplasia, of the medial collateral ligament. The osseous deformities consisted of outward rotation of the proximal ulna, hypoplasia, or aplasia, of the coronoid process, anconeal process and radial notch and a shallow trochlear notch. The proximal ulna was rotated approximately 40–45°. The olecranon was deviated laterally and dorso-cranially. The syndrome was compared with the deformities of congenital luxation of the radial head in children. An embryonic pathogenesis for congenital elbow luxations in dogs was hypothesized.

A new radiological sign has been observed in 14 of 236 elbows of haemophiliacs examined. This finding is a widening of the radial notch of the ulna, which may become extremely large.